There were a few isolated issues as well that may or may not be related. At a screening in San Francisco, the issues weren’t the same, but the theater couldn’t handle Interstellar. Film Drunk has a story about how a screening was canceled because of the sound. Here are some tweets to back it up.

Even this review from Moviefone, which was written out of New York, reported issues:

There were those at our screening that indicated that there were some issues with “audio bleed,” or dialogue getting lost in the cacophonous shuffle of sound effects, score, and whatever the hell else is going on inside the swirling vortex of “Interstellar.” And truth be told, we also noticed that too; sometimes bits of dialogue here and there would just disappear. But “Interstellar” is an insanely rich visual experience and a lot of the dialogue is expository in nature, simply explaining how characters are getting from point a to point b (or something). In other words: the dialogue isn’t super important, even if you miss out on some stuff, it won’t matter much in the end.

So is this just an IMAX issue? Not at all. Peter Sciretta saw the movie on 70mm IMAX and then 35mm film and reported similar issues:

I saw it in 35mm at the Arclight Hollywood and the sound is not as bad as the IMAX Chinese but there are still moments where it’s hard to understand what people are saying, usually because the score or sound effects are blaring loudly.